White matter hyperintensities and working memory: an explorative study

White matter hyperintensities (WMH) are commonly observed in elderly people and may have the most profound effect on executive functions, including working memory. Surprisingly, the Digit Span backward, a frequently employed working memory task, reveals no association with WMH. In the present study, it was investigated whether more detailed analyses of WMH variables and study sample selection are important when establishing a possible relationship between the Digit Span backward and WMH. To accomplish this, the Digit Span backward and additional working memory tests, WMH subscores, and cardiovascular risk factors were examined. The results revealed that performance on the Digit Span backward test is unrelated to WMH, whereas a relationship between other working memory tests and WMH was confirmed. Furthermore, a division between several white matter regions seems important; hyperintensities in the frontal deep white matter regions were the strongest predictor of working memory performance.     

Neural basis of affective touch and pain: A novel model suggests possible targets for pain amelioration

Pain is one of the most common health problems and has a severe impact on quality of life. Yet, a suitable and efficient treatment is still not available for all patient populations suffering from pain. Interestingly, recent research shows that low threshold mechanosensory C-tactile (CT) fibres have a modulatory influence on pain. CT-fibres are activated by slow gentle stroking of the hairy skin, providing a pleasant sensation. Consequently, slow gentle stroking is known as affective touch. Currently, a clear overview of the way affective touch modulates pain, at a neural level, is missing. This review aims to present such an overview. To explain the interaction between affective touch and pain, first the neural basis of the affective touch system and the neural processing of pain will be described. To clarify these systems, a schematic illustration will be provided in every section. Hereafter, a novel model of interactions between affective touch and pain systems will be introduced. Finally, since affective touch might be suitable as a new treatment for chronic pain, possible clinical implications will be discussed.     

White Matter Hyperintensities and Working Memory: An Explorative Study

ABSTRACT

White matter hyperintensities (WMH) are commonly observed in elderly people and may have the most profound effect on executive functions, including working memory. Surprisingly, the Digit Span backward, a frequently employed working memory task, reveals no association with WMH. In the present study, it was investigated whether more detailed analyses of WMH variables and study sample selection are important when establishing a possible relationship between the Digit Span backward and WMH. To accomplish this, the Digit Span backward and additional working memory tests, WMH subscores, and cardiovascular risk factors were examined. The results revealed that performance on the Digit Span backward test is unrelated to WMH, whereas a relationship between other working memory tests and WMH was confirmed. Furthermore, a division between several white matter regions seems important; hyperintensities in the frontal deep white matter regions were the strongest predictor of working memory performance.     

The role of white matter hyperintensities and medial temporal lobe atrophy in age-related executive dysfunctioning

Various studies support an association between white matter hyperintensities (WMH) and deficits in executive function in nondemented ageing. Studies examining executive functions and WMH have generally adopted executive function as a phrase including various functions such as flexibility, inhibition, and working memory. However, these functions include distinctive cognitive processes and not all may be affected as a result of WMH. Furthermore, atrophy of the medial temporal lobe (MTA) is frequently observed in ageing. Nevertheless, in previous studies of nondemented ageing MTA was not considered when examining a relationship between white matter and executive function. The goal of the present study was to examine how WMH and MTA relate to a variety of executive functions, including flexibility, fluency, inhibition, planning, set shifting, and working memory. Strong correlations were observed between WMH and MTA and most of the executive functions. However, only MTA was related to flexibility and set shifting performance. Regression analysis furthermore showed that MTA was the strongest predictor of working memory, after which no further significant association with WMH was noted. Alternatively, both MTA and periventricular hyperintensities independently predicted inhibition performance. These findings emphasize the importance of MTA when examining age-related decline in executive functioning.     

Rehearsal strategies during motor-sequence learning in old age: execution vs motor imagery

Motor imagery and action-based rehearsal were compared during motor sequence-learning by young adults (M = 25 yr., SD = 3) and aged adults (M = 63 yr., SD = 7). General accuracy of aged adults was lower than that of young adults (F(1,28) = 7.37, p =.01) even though working-memory capacity was equivalent in the two groups. Motor imagery and rehearsal by action increased accuracy in both age groups, compared with minimization of opportunity for rehearsal (F(1,28) = 30.95, p < .001), but no interaction was found with age group, which suggests that young and aged adults were equally capable of motor imagery and action-based rehearsal. It was assumed that differences in performance between young and aged participants related to the formation of mental representations of sequences and integration of new elements into these representations rather than the capacity for motor imagery or rehearsal by action per se. The current study was exploratory and involved a relatively small sample of 15 participants per age group. Caution must be taken when considering the results.     

Motor-Skill Learning in Alzheimer’s Disease: A Review with an Eye to the Clinical Practice

Since elderly people suffering from dementia want to go on living independently for as long as possible, they need to be able to maintain familiar and learn new practical skills. Although explicit or declarative learning methods are mostly used to train new skills, it is hypothesized that implicit or procedural techniques may be more effective in this population. The present review discusses 23 experimental studies on implicit motor-skill learning in patients with Alzheimer’s disease (AD). All studies found intact implicit motor-learning capacities. Subsequently, it is elaborated how these intact learning abilities can be exploited in the patients’ rehabilitation with respect to the variables ‘practice’ and ‘feedback.’ Recommendations for future research are provided, and it is concluded that if training programs are adjusted to specific needs and abilities, older people with AD are well able to (re)learn practical motor skills, which may enhance their autonomy.